In a work vehicle such as an excavator, an operator, who is riding in a cab, has a clear view to the front of the cab, and accordingly can easily and visually perceive things such as an obstacle existing in front of the work vehicle. On the other hand, an engine hood, a counterweight, and the like cut the visibility to the side and rear of the cab and accordingly the obstacle and the like may be hard to be visually checked.
Hence, a camera is installed at places such as the rear of an upper swing structure of the work vehicle to make it possible to always display video captured by the camera as a standard screen on a display screen of a display device provided in the cab. Consequently, the operator can check an area having poor visibility through the display screen in cases such as where the work vehicle travels back and where the upper swing structure swings around.
For example, in Patent Literature 1, the camera's rear view image acquired by the camera is displayed on the entire display screen while the camera's image is displayed so as to be seen through a measurement data image by superimposing the measurement data image on the camera's image.